Tube bank heat exchanger with supports



March 21, 1967 J. F. TILLEQUIN 3,310,104

TUBE BANK HEAT EXCHANGER' WITH SUPPORTS Filed Dec. 25, 1965 4 Sheets-Sheet 1 /N VE N TOIZ Jean F. Tillequin ATTORNEY March 21, 1967 J. F. TlLLEQUlN 3,310,104

TUBE BANK HEAT EXCHANGER WITH SUPPORTS Fil ed Dec. 25, 1965 4 Sheets-Sheet z March 21, 1967 Filed Dec. 23, 1963 J. F. TILLEQUIN TUBE BANK HEAT EXCHANGER WITH SUPPORTS 4 Sheets-Sheet :5

March 21, 1967 .J. F. TILLEQUIN 3,310,104

TUBE BANK HEAT EXCHANGER WITH SUPPORTS Filed Dec. 23, 1963 4 Sheets-Sheet United States Patent 3,310,104 TUBE BANK HEAT EXCHANGER WITH SUPPORTS Jean Frederic Tillequin, Paris, France, assignor to Babcock & Wilcox, Limited, London, England, a corporation of Great Britain Filed Dec. 23, 1963, Ser. No. 332,796 Claims priority, application France, Dec. 29, 1962, 920,186, Patent 1,351,602 3 Claims. (Cl. 165-145) This invention relates to tubu'lous heat exchangers adapted to efiect heat exchange between a fluid flowing within the tubes thereof and a fluid passing over the tube surfaces. More particularly, the invention relates to heat exchangers arranged to form a vapour generating and superheating unit for use in conjunction with a gas-cooled nuclear reactor.

A tubulous heat exchanger according to the present invention includes a casing of hexagonal prismatic form and three tube banks of identical rhombic prismatic form respectively disposed in spaces subtended by adjacent pairs of sides of the casing and extending to the longitudinal central axis thereof, the tube banks each including tubes having straight tube lengths connected by return bends and disposed parallel to one of the associated sides of the casing.

The invention will now be described by way of example, with reference to the accompanying, partly diagrammatic drawings, in which:

FIGURE 1 is a section elevation taken on the line I-I of FIGURE 2 of a steam generating and superheating unit positioned in a cylindrical duct;

FIGURE 2 is a plan view of the unit;

FIGURE 3 is a view in perspective to an enlarged scale of a part of a casing of the unit;

FIGURE 4 is a plan view of suspension means for the unit;

FIGURE 5 is a view in perspective, to an enlarged scale, of a tube bank shown in FIGURES 1 and 2, consisting of sinuous tube lengths extending in parallel between a pair of headers;

FIGURE 6 is a view in perspective, to an enlarged scale, of an alternative form of tube bank consisting of sinuous tube lengths extending in parallel between two pairs of headers;

FIGURE 7 is a sectional elevation of a portion of a unit arranged for use in conjunction with a nuclear reactor;

FIGURE 8 is a sectional plan view taken on the line VIII-VIII of FIGURE 7 of part of a superheater section of the unit; and

FIGURE 9 is a sectional plan View taken on the line IXIX of FIGURE 7 of part of an economiser section of the unit.

Referring to FIGURES 1 to 5 of the drawings, there is shown a cylindrical duct 10 arranged to be traversed from top to bottom by a flow of hot gas, from a source not illustrated, and a steam generating and superheating unit 9, including, from bottom to top, an economiser section 11, an evaporator section 12 and a superheater section 13. Each of the sections 11, 12 and 13 is positioned in a casing 15, which, as is shown in FIGURE 3, is of hexagonal prismatic shape made up of six rectangular plates welded together at adjacent edges and reinforced externally with I-section beams 16. Welded to the edge of the casing 15 is a flange 17 which forms a tight connection with the internal surface of the wall of the duct 10.

Within the hexagonal prismatic space surrounded by the casing 15 of the superheater 13 are positioned three tube banks 21, 22, 23, each of rhombic prismatic shape and disposed in the spaces formed between three, equiangularly spaced, radially extending, upright, planes 24, 25, 26 and the walls of the casing 15. Thus the tube bank 21, is disposed between the radially extending planes 24, 25 and the walls 27, 28 of the casing 15 and extends between a lower inlet header 31 and an upper outlet header 32, and is formed by rows of tubes 33 each including a plurality of straight tube lengths connected by return bends, the straight tube lengths extending parallel to the radial plane 25 and the two associated headers 31, 32 extending parallel to the radial plane 24. The two other tube banks 22 and 23 are formed in a similar manner, with straight tube lengths respectively parallel to the radial planes 26 and 24.

The tube banks of the evaporator 12 and economiser 11 are formed and arranged in a similar manner to those of the superheater 13.

In order to support the tube banks, there is provided inside the duct 10, as is shown diagrammatically in FIG- URE 4, a central column 41 and six peripheral columns 42 constituted by reinforcements provided at the angles of the respective casings 15. The columns 41, 42 support three radial beams 43, 44, 45 from the outer ends of which extend respective external beams 46, 47, 48. Each pair of parallel beams, 43 and 48, 44 and 46, 45 and 47 support cross-bars 49 from which the tubes making up the subjacent tube bank 23, 21, 22 are supported.

In the arrangement shown in FIGURE 1, the tube banks respectively forming the three sections 11, 12, 13 are arranged in parallel flow paths, each tube bank of a section being connected to the adjacent tube bank in the adjacent sections. Thus, three panallel steam flow paths are formed, one steam flow path for example commencing at a feed header 51 of the economiser 11, extending through an adjacent tube bank 11A to an outlet header 52 of the section, a connecting tube 53, an inlet header 54 of a corresponding tube bank 12A of the evaporator 12, an outlet header 55, a connecting tube 56, the inlet header 31 of the corresponding tube bank 21 of the superheater 13 and the outlet header 32 to a superheated steam outlet main 57. The three feed headers 51 and the three outlet mains 57 extend to respective common connections (not shown) which ensure even distribution of water between the flow paths and even cooling of the hot gases flowing through the duct 19.

It will be appreciated that this arrangement makes it possible to lodge one or more heat exchangers in a particularly compact manner in a duct which is cylindrical or comprises a series of cylindrical sections, with an economy of space and communication pipework between heat exchanger elements.

It will also be appreciated that since all of the tube surfaces of the steam generating and snperheating unit may be positioned in the duct, it will be sufiicient to provide in the duct passageways for only the water inlet main and the steam outlet main.

FIGURE 6 shows an alternative form of tube bank in which a first row of sinuous tubes 33A extends from a header 31A to a header 32A and a second row of sinuous tubes 33B extends from a header 318 to a header 32B with the tubes 33A of the first row alternating with the tubes 33B of the second row across the tube bank. This arrangement provides flow paths through each tube bank, which flow paths may be led to separate utilisation means or combined without producing uneven cooling of the hot gases flowing through the duct 10.

FIGURES 7 to 9 show an arrangement of a steam generating and superheating unit 58 arranged for use in conjunction with a gas-cooled nuclear reactor (not shown). The nuclear reactor and the unit 58 are disposed within a biological enclosure 60 of pre-stressed concrete having a cylindrical shape with a vertical axis, the unit 58 being positioned below the reactor, the core of which is positioned above a biological screen. The coolant gases traverse the core from top to bottom, flow round the biological screen 61, and are discharged to a duct 59 which comprises, from top to bottom, an upper cylindrical section 62, a convergent frusto-conical shaped section '63, an intermediate cylindrical section 64, a divergent frusto-conical section 65 and a second lower cylindrical section 66 terminating somewhat above a bottom 67 of the enclosure 60. At the level of the divergent frusto-conical section 65, the enclosure 60 is formed with niches 70 each containing a blower (not shown) which draws in, in the direction of arrow 71, the coolant gases rising in an annular space 68 formed between the section 66 and the enclosure 60 and discharges the gases in the direction of arrow 72 towards the top of the reactor enclosure 60 for recirculation to the reactor.

The unit 58 comprises from top to bottom, a superheater section 80 positioned within the intermediate cylindrical section 64 and an evaporator section 90 and an economiser section 100 positioned, the one above the other, in the lower cylindrical section 66 of the duct 59, each of the sections 80, 90, 100 being constructed basically as hereinbefore described in conjunction with FIGURES 1 to as modified by FIGURE 6 inside a hexagonal prismatic casing divided into three rhombic prismatic portions.

However, in contradistinction to the hereinbefore described arrangement, each portion of the superheater 80, such as that shown at 81 in FIGURE 8 is divided into two further equal portions 82, 83 each having the shape of a parallelepiped and being formed by a secondary tube bank comprising two rows of sinuous tubes with the tubes of one row alternating with tubes of the other row across the bank and respectively connected between lower inlet headers 85A, 85B and upper outlet headers 86A, 86B. Superheated steam mains 87A, linking the six outlet headers such as 86A are grouped in parallel and connected to an outlet main 88A, while the steam mains 87B linking the six outlet headers 86B are also grouped in parallel and connected to an outlet main 88B, apertures for the passage of the steam mains 87A, 87B being provided in a flange 89 of the casing of the superheater section 80 and junctions between mains being effected in the space surrounded by the divergent frusto-conical section 65 of the duct 59. The steam outlet mains 88A, 88B pass through apertures in the divergent frusto-conical section 65 of the duct 59 and through one of the apertures 70 in the enclosure 60 to utilising means (not shown).

The economiser 100 is divided into three portions 101, one of which is shown in FIGURE 9, of rhombic prismatic shape, each of which is sub-divided into six equal portions 102, each having the shape of a parallelepiped and being formed by a secondary tube bank comprising two rows of sinuous tubes with the tubes of one row alternating with tubes of the other row across the bank and respectively connected between two inlet headers 103A, 103B, positioned the one above the other, and two outlet headers 104A, 1043. The eighteen inlet headers 103A are connected to a feed header 105A and the eighteen inlet headers 103B to a feed header 105B, the feed headers 105A, 105B being respectively connected in turn to feed mains 106A, 106B passing through one of the apertures 70 in the biological enclosure 60.

The evaporator 90 is subdivided, in a manner similar to the sub-division of the economiser 100, into eighteen portions each having the shape of a parallelepiped and each outlet header 104A or 104B of each portion 102 of the economiser is connected by a connecting tube 92 to an inlet header 93A or 93B of a corresponding portion of the evaporator 90 immediately above the former. The eighteen headers 94A, and the eighteen headers 94B of the evaporator 90 are connected in threes, by connectors 95A, 95B, to the inlet headers 85A, 85B of the superadjacent portions of the superheater 80.

Thus, two independent water-steam circuits are provided having separate feed water inlet mains 106A, 10613 and separate superheated steam outlet mains 88A, 8813, thereby making it possible in the event of a breakdown associated with one water-steam circuit, such as failure of a turboalternator unit supplied by steam from the circuit, or failure of associated feed pumps, evenly to extract heat from the coolant gases since in all sections of the unit 58 one tube out of two may be maintained in operation.

It will be appreciated that since a rhombus is divisible into further, similar, rhombi, or into similar parallelograms, a number of tube banks of the form of a rhombic prism, or of the form of a parallelepiped, having an angle of between a pair of adjacent sides, of a single basic size, may be utilized to construct larger tube banks, as is indicated in FIGURES 7 to 9, thereby effecting an economy in basic construction costs.

I claim:

1. A tubulous heat exchanger including an elongated casing of hexagonal prismatic form arranged with its longitudinal central axis in an upright position, three tube banks of identical rhombic prismatic form disposed within and substantially filling said casing, each of said tube banks disposed with a space subtended on two sides by an adjacent pair of sides of said casing and extending along the other two sides from the casing to the longitudinal central axis of the casing, said tube banks each including tubes having straight tube lengths connected by return bends, said straight tube lengths disposed parallel to one of said adjacent pair of sides of said casing which bound the space containing the tube lengths, a vertical column located along said central axis, a plurality of vertical columns each located at one of the corners of said casing, a pair of spaced parallel support beams for each of said tube banks, one of said beams extending between columns located at adjacent corners of said casing and parallel with the said straight tube lengths of the adjacent tube banks and the other said beam extending between said column along the said central axis and a column located in a corner of the casing, and a number of crossbars mounted on said pair of beams for supporting the tubes in said tube bank.

2. A tubulous heat exchanger including an elongated casing of hexagonal prismatic form, three tube banks of identical rhombic prismatic form disposed within and substantially filling said casing, each of said tube banks disposed within a space subtended on two sides by an adjacent pair of sides of said casing and extending along the other two sides from the casing to the longitudinal central axis of the casing, said tube banks each including tubes having straight tube lengths connected by return bends, said straight tube lengths disposed parallel to one of said adjacent pair of sides of said casing which bound the space containing the tube lengths, each of said tube banks comprising a plurality of heat exchangers disposed serially in vertical alignment within corresponding tube banks in vertically adjacent heat exchangers connected in series to form a plurality of parallel vapor generating and superheating paths through the unit, each of said tube banks 5 being sub-divided into a plurality of secondary tube banks of parallelepiped form.

3. A tu-bulous vapour generating and superheating unit as set forth in claim 2 wherein each of said secondary tube banks is provided with an inlet header and an outlet header, and the outlet headers of the secondary tube banks of one tube bank are connected to the inlet header of a corresponding secondary tube bank in the superjacent heat exchanger.

References Cited by the Examiner UNITED STATES PATENTS 2,946,732 8/1960 Wootton 17660 6 3,104,652 9/1963 Tillequin et a1. 122-32 3,110,288 11/1963 Worley 12232 3,183,969 5/1965 Bell 165-160 FOREIGN PATENTS 865,426 4/ 1961 Great Britain.

900,821 8/ 1962 Great Britain. 1,272,920 8/ 1961 France.

287,673 4/ 1953 Switzerland.

ROBERT A. OLEARY, Primary Examiner. L. DEWAYNE RUTLEDGE, Examiner. A. W. DAVIS, Assistant Examiner. 

1. A TUBULOUS HEAT EXCHANGER INCLUDING AN ELONGATED CASING OF HEXAGONAL PRISMATIC FORM ARRANGED WITH ITS LONGITUDINAL CENTRAL AXIS IN AN UPRIGHT POSITION, THREE TUBE BANKS OF IDENTICAL RHOMBIC PRISMATIC FORM DISPOSED WITHIN AND SUBSTANTIALLY FILLING SAID CASING, EACH OF SAID TUBE BANKS DISPOSED WITH A SPACE SUBTENDED ON TWO SIDES BY AN ADJACENT PAIR OF SIDES OF SAID CASING AND EXTENDING ALONG THE OTHER TWO SIDES FROM THE CASING TO THE LONGITUDINAL CENTRAL AXIS OF THE CASING, SAID TUBE BANKS EACH INCLUDING TUBES HAVING STRAIGHT TUBE LENGTHS CONNECTED BY RETURN BENDS, SAID STRAIGHT TUBE LENGTHS DISPOSED PARALLEL TO ONE OF SAID ADJACENT PAIR OF SIDES OF SAID CASING WHICH BOUND THE SPACE CONTAINING THE TUBE LENGTHS, A VERTICAL COLUMN LOCATED ALONG SAID CENTRAL AXIS, A PLURALITY OF VERTICAL COLUMNS EACH LOCATED AT ONE OF THE CORNERS OF SAID CASING, A PAIR OF SPACED PARALLEL SUPPORT BEAMS FOR EACH OF SAID TUBE BANKS, ONE OF SAID BEAMS EXTENDING BETWEEN COLUMNS LOCATED AT ADJACENT CORNERS OF SAID CASING AND PARALLEL WITH THE SAID STRAIGHT TUBE LENGTHS OF THE ADJACENT TUBE BANKS AND THE OTHER SAID BEAM EXTENDING BETWEEN SAID COLUMN ALONG THE SAID CENTRAL AXIS AND A COLUMN LOCATED IN A CORNER OF THE CASING, AND A NUMBER OF CROSSBARS MOUNTED ON SAID PAIR OF BEAMS FOR SUPPORTING THE TUBES IN SAID TUBE BANK. 